Push-button electric switch and cover plate therefor



1,787,210 PUSH BUTTON ELECTRIC SWITCH AND COVER PLATE THEREFOE Dec. 30,1.930. G. w. OKEEFFE Filed June 27, 1928 W WW I.

Patented Dec. 30, 1930 UNETED STATES PATENT OFFICE GEORGE W. OKEEFFE, OFMILTON, MASSACHUSETTS, ASSIGNOR TO CONDIT ELEC- TRICAL MANUFACTURINGCORPORATION, OF

CORPORATION OF MASSACHUSETTS PUSH-BUTTON ELECTRIC SWITCH AND COVER PLATETHEREFOR Application fiiea'iune 2?,

10 cated at a distance from the point of control.

A dangerous situation arises when the motors or the apparatus connectedthereto or associated therewith are being repaired, and in spite of thecustomary precautions taken,

15 it has frequently happened that the switch has been carelessly oraccidentally operated and injury has resulted.

It is an object of this invention to provide an accessory device for apush button control switch whereby to render the switch temporarilyinoperative to control the circuit.

The control switch is usually adapted to control the operation of anelectromagnetic switch and has a start button to close the a.electro-magnetic switch and a stop button to open the electro-magneticswitch. Said switch includes a winding or coil which is energizedinitially by the momentary depressing of the start buttonto effect theclosing of the switch which, when closed, completes a holding circuitthrough the coil to keep the coil energized and the switch closed. Theholding circuit is opened by momentarily depressing the stop button,whereby to 5 open the switch. It is therefore possible, by manualoperation of the electro-magnetic switch, to close the motor circuiteven though the push button control switch be enclosed in a lockedcabinet. Under these circumstances the motor circuit will remainenergized until the stop button is depressed, due to the holding coil. 8

It is therefore a further object of this invention to provide suitablemeans for preventing access to the control buttons of the switch whichwill also disable the holding coil circuit of the electro-magnetic lineswitch.

Another object is the provision of a lockout plate which will cover bothpush but- 0 tons of the control switch, so that they can- 1928. SerialNo. 288,726.

SOUTH BOSTON, MASSACHUSETTS, A

not be operated readily, and also will hold I casing partly broken away.

Fig. 3 is a front elevation of the lockout plate.

Fig. 4 is a side elevation of the lockout plate of Fig. 3.

Fig. 5 is a perspective view of the plateholding screw.

Fig. 6 is a diagram of the connections of a remote control push buttonswitch with which the invention is concerned and an electro-magneticswitch controlled thereby.

As herein shown the invention is illustrated in connectionwith a remotecontrol switch A (Fig. 6) which is adapted to control the operation of amotor 13 by means of an electro-magnetic'line cont-actor or switch C.Said control switch A comprises specifically a pair of selectivelyoperable movable switch members 10 and 12 having a common pivotalsupport at 13 on a terminal member 14 which is secured to an insulatingbase 15'.

Said movable switch members are provided with radial arms 16 havinginwardly-directed, overlapping arcuate extensions 18, and a compressionspring 20 is disposed loosely on saidextensions 18 with its cppositeends in engagement with said arms 16, whereby to bias them constantlyinto a normal position against abutments 22 on said terminal member 14.Means are provided to move said switch members 10 and .12 away from saidabutments 22 against the bias of the spring 20. Said means comprise thepush buttons 24 and 26 provided with posts 28, which are pivotallyconnected at 30 and 32 to said arms 10 and 12 respectively. Said buttonsare guided for straight line motion by aframe 34:, secured to saidinsulating base 15, which frame has suitable apertures 35 therein toreceive said buttons.

Fixed contact members, comprising the U-shaped resilient clips 36 and38, are sup butcooperating movable switch member 12 is in engagementtherewith when in its normal position against its abutment 22. Theinsulating base 15 and the switch assembly mounted therein is securedremovably within a casing 37 by means of suitable bolts ere tendedthrough the frame 34 into said casit cover provides the front closurefor saic casing 37 and comprises a substantially rectangular flat plate40 which is acapted to overlie sai'd'frame 34, an integral outwardlyflared peripheral flange 42, and a substantially rectangular frame 43which lies flush with the front edge of the casing 37. Said rectangularframe 43 is further provided with an angularly related peripheral flange44 which fits closely about the side walls of the casing 3? to provide aweather-tight joint thereabout, and also to prevent relative movement ofsaid cover and the casing 37. Said cover plate 40 is provided withapertures to receive the buttons 24 and 26 which are aligned with theapertures '35 in frame 34, and a bolt 46 is extended loosely through theplate and is screw threaded into the frame 34, whereby to secure thecover removably to the frame '34 and thus to the casing 37. The outerend of said buttons 24 and 26 in their normal position are adapted tolie'somewhat beneath the frame 43 whereby to be protected fromaccidental blows. The details of construction of the bush-button switchare described more particularly and are claimed in my copendingapplication, Serial No. 228,725, iil'ed June 27, 1928.

As shown in Fig. 6, the movable switch member 10 and the fixed contact36 comprise an energizing switchtor the electromagnetic switch C and,upon depressin the start button 24, complete a circuit including theline conductor 48, switch arm 10, contact 36, winding and line conductor54, thus to close the electro-magnetic switch 0 and, through the latter,the circuit through motor B. The closing of the electro-magnetic switchalso completes a holding circuit for itself. Said holding circuitincludes the line conductor 48 the second switch arm 1-2 of the pushbutton switch, contact 38, auxiliary contacts 52, winding 50, and lineconductor 54. Upon depression of the stop button 26, the holding circuitis opened and the coil 50 is deenergized, thus opening the 'ele'ctro-'magnetic switch. This is a more or less common arrangement for theremote control of electric motors.

When it becomes necessary to make repairs or for any reason to work onthe motor B, or the machine connected thereto, it is essential that thecontrol switch A be rendered inoperative to energize the electromagneticswitch C. To this end, a substantially flat rectangular lock-out plate56 is provided, see Figs. 3 and 4, which plate is adapted to lie withinthe depression of the cover of the control switch and flush with saidframe 43 and with its periphery bearing against the outwardly flaredflange 42 thereof. As shown in Fig.2 said lock-plate 56 when in positionon the switch cover completely covers said plate 40 and the flange 42thereof and is spaced slightly from .the extended end of button 24. Saidlockplate is further provided with a struck-out portion 58 having a flatextended face '59 whichconforins with theend of said button 26,

and whichenga-ges and holds said stopbutton 26 depressed when saidlock-plate is in the position illustrated in Fig. '2, whereby the switcharm 12 of the stop switch is held out of contact withits cooperating,contact 38, and the holding coil circuit includingwinding 50 thus ismaintained open.

The bolt46 which secures the cover to the casing 37 is located at oneside of the vertical center line thereof which includes the push buttonsand is provided with a some- "what enlarged head '60 which is internallyscrew threaded to receive a screw 62 which extends through a hole 63 inthe lock p'late 56 to hold thecover plate on the switch casing. Thescrew 62 is adapt-ed normally to remain. in the enlarged head and thusto be available whenever it is desired to attach the lock-plate. By theprovision of an eccentrically located attaching bolt tor the l'oclnoutplate, itis impossible. to secure the plate to the casing .in a positionto depress the startbutton.

With the lock-out plate in position, as shown in Figs. 1 and '2, thestart button is wholly inaccessible, and the stop button 26 ismaintained in a depressed position by the struck-out portion 58 so thatthe contact 38 is free from engagement with the switch arm 12 and underno circumstance can the holding coil circuit be completed through thewinding 50-of the line contactor C.

I claim 2 1. In an electric switch, the combination of an enclosingcasing, a pair of switch operating push buttons extended through andbeyond the outer wall of said casing, means separate from said casinghaving means to ai'fix it temporarily to said casing and when afliX-edto said casing arranged to cooperate herewith to enclose the extendedends of both push buttons and also to maintain one only of said pushbuttons in a depressed position.

2. In an electric switch, the combination of an enclosing casing havingtwo pairs of stationary and movable switch members therein, a pushbutton operatively associated with each of the movable switch memberswithin said casing and movably extended through and outwardly beyond thewall of said casing, means to bias said movable switch members normally.into a position whereby said push buttons are extended into theaforesaid position beyond said casing wall, and detachable meanscooperating with said casing to enclose the extended end of both buttonsand also to depress one of said buttons against said biasing means.

3. A push button electric switch having a casing, two selectivelyoperable movable switch members within the casing, a push button foreach of said movable switch members slidably received in said casing,means to bias said push buttons normally into position to project from.said casing, and a lockout plate for said switch arranged to cooperatewith said casing to enclose the proj ecting ends of said push buttonsand having means to engage and maintain one of said buttons depressedagainst said biasing means.

4. A push button electric switch having a casing, two sets ofcooperating stationary and movable switch members disposed within saidcasing, apair of push buttons projecting from said casing for operatingsaid movable switch members selectively, means normally biasing one ofSaid sets of switch membersout of engagement and the other of said setsinto engagement, and a lock out member having a detachable connectionwith said casing arranged to enclose the projecting ends of said pushbuttons, said lock-out member also provided with means to engage anddepress the push button of said second set of switch members whereby tomaintain said switch members out of engagement.

5. A push button electric switch having an enclosing casing, cooperatingstationary and movable switch members within said casing,

said movable switch member being biased into engagement with itscooperating stationary switch member, a push button projecting from saidcasing for operating said movable switch member against its bias into aposition free from engagement with said stationary switch member, alock-out plate having a detachable connection with said casing, saidplate having a projection there of in position to engage and maintainsaid push button in position to hold said stationary and movable switchmembers out of engagement against said biasing means.

6. A push button switch having an enclosing casing, a pair ofcooperating stationary and movable contact members within said buttonprojecting from said a lock-out plate means securing said casing, saidmovable contact member being biased out of engagement with itscooperating stationary contact member, a push button projecting fromsaid casing for operating said movable contact member against its biasto effect the engagement thereof with its cooperating stationary contactmember, a second pair of-stationary and movable contact members withinsaid casing normally biased into engagement, a push button projectingfrom said casing for operating said second movable contact memberagainst its bias to separate it from engagement with its cooperatingstationary contact member, and a lockout plate cooperating with saidcasing to enclose both of said buttons, said lock-out plate also havinga projection arranged to engage and depress said second push button andmaintain said second contact members out of engagement.

7. A push button electric switch having an enclosing casing, a pair ofcooperating stationary and movable contact members within said casing,said movable contact member being biased out of engagement with itscooperating stationary contact member, a push casing for operating saidmovable contact member against its bias to effect the engagement thereofwith its cooperating stationary contact member, a second pair ofstationary and movable contactmembers within said casing normally biasedinto engagement, a push button projecting from said casing'for operatingsaid second movable contact member. against its bias to separate it fromengagement with its cooperating stationary contact member, cooperatingwith said casing to enclose said push buttons and having a projectionarranged toengage and maintain said second push button in a depressedposition, said lock-out plate having a detachable connection with saidswitch casing located eccentrically thereof, whereby to prevent theattachment of said plate in an inverted position. i

8. An electric switch having a casing and a pair of superposed switchoperating push buttons projectingtherefrom, means to bias said pushbuttons into the aforesaid position, and a guard member adapted to beaffixed removably to said casing arranged to overlie the projecting endsof said push buttons, said guard member also having a pro jectionthereon arranged when said member is afiiXed to said casing to engageand hold one of said push buttons depressed, and guard member to saidcasing located eccentrically thereof so that said guard member cannot beimproperly affixed to the casing.

9. An electric switch including an enclosing casing having asubstantially rectangular recess in an outer face thereof, a pair ofsuperposed push buttons projecting from said casing :intosai-d recess,.a plate disposed within and conforming to the said recess and spacedfrom the projecting ends of said buttons, said'plate havin a struck-outportion arran ed to-engage and depress one of said buttons, and anattaching bolt passed loosely through said plate and screw threaded intosaid casing, said attaching bolt being disposed at one side of a linethrough said superposed buttons. 7

10. A lock-out device for an electric switch hold it depressed, saidplate having an attaching hole therethrough which is located at onesideof the longitudinal axis of the plate.

In testimony whereof, I have signed my name to this specification.

GEORGE W. OKEEFFE.

of the type having an enclosing casing and two switch I operatingbuttons projecting from a wall thereof, comprising a cover for .1 saidcasing wall overlying and spaced from said cover attached to saidcasing, a rectangular safety plate occupying said depression above saidpush buttons and having a projection which engages one of said pushbuttons and holdsit depressed, and a screw passed through saidsafetyplate at one side of the line of said push buttons and having ascrew threaded engagement with said cover holding screw.

12. A push button electric switch having an enclosing casing, pushbuttons projecting therefrom, and a cover'plate located on said casingover said push buttons above and out of engagement with one of saidbuttons and having a projection which is located above and bears againstanother of said buttons whereby to maintain it depressed, and means tosecure said plate only in the aforesaid relation on said casing. 7 13. Apush button electric switch having an enclosing casing, push buttonsprojecting therefrom, and a cover plate located .on said casing oversaid push buttons above and out of engagement with one of said buttonsand having a projection which is located above and bears against anotherof said buttons whereby to maintain it depressed, and attaching meanspassed through said plate at one side of a line passed through said pushbuttons and connected with said casing, whereby to secure said plateonly in the afore said relation to said casing.

14. A safety plate for a push button switch having a pair of extendedpush buttons, which plate is rigid, flat and rectangular and has anintegral struck-out boss that is adapted. to overlie and engage one pushbutton and

